Fluid pressure operated dampers of the dual type



C. A. OTTO Oct. 11, 1955 FLUID PRESSURE OPERATED DAMPERS OF THE DUALTYPE Original Filed March 29, 1951 \\\\w g g LQQM QE? EJEVWEZ/QJG W hATTORNEYS United States PatentO FLUID PRESSURE OPERATED DAMPERS OF THEDUAL TYPE Carl A. Otto, Milwaukee, Wis., assignor to Johnson ServiceCompany, Milwaukee, Wis., a corporation of Wisconsin Originalapplication March 29, 1951, Serial No. 218,140. Divided and thisapplication December 7, 1953, Serial No. 397,290

2 Claims. (Cl. 137-595) This invention relates topressure-motor-operated dampers, and can be embodied in single dampersand in dual or mixing dampers. The present application is restricted todual dampers, and is a division of application Serial No. 218,140 filedMarch 29, 1951, from which applicant was required to remove claimsdirected to dual dampers. One outstanding advantage of the invention isthe ease with which the damper can be designed to afford specialflow-rate characteristics by changing the contour of the ports.

Important space economies are made possible by the fact that the motorand damper are combined in a single moving part which is short and canbe mounted within the duct or an extension thereof.

Two typical embodiments will now be described by reference to theaccompanying drawings, in which:

Fig. 1 is an axial section of two axially alined duets with a duplexdamper and differential actuating motor interposed between the proximateends of the ducts.

Fig. 2 is a similar section showing a modified type of duplex damper inwhich the motor includes a sleeve which encircles the ends of the ductsand shifts in the direction of its axis.

It is characteristic of the invention that a tubular rubber-like sleevefolded through itself rolls between two coaxial cylindrical surfaces tofunction simultaneously l) as a rolling seal between two relativelymovable parts of an expansible chamber motor and (2) as a valve whichobstructs or exposes progressively ports formed in one of thecylindrical surfaces. In this way the motor and the damper are a singleunit and occupy little more space than that necessary for the motoralone. The whole thing can be housed in a prolongation of the duct withwhich it is associated.

A dual damper constructed according to the invention controls flow to orfrom two axially alined ducts and is interposed between the proximateends of the ducts. This pre-supposes two sets of ports, one set for eachduct, and two rolling sleeves each controlling the ports of acorresponding duct. Since there need be only one motor, the two sealsformed by the sleeves are associated with opposite ends of adifferential motor of the expansible chamber type. Such a motor issingle acting and consequently biasing means, usually of the springtype, are used.

Fig. 1 shows an embodiment in which the moving parts are within thedimensional limits of the ducts and are enclosed.

A familiar field of use is to control simultaneously in inverse sensesthe flow of two media to a mixing chamber. For convenience in discussionthe fluids will be called warm air and cold air.

Assume that 41 is a warm air duct and 42 the cold air duct. They lead totwo flanged valve bodies 43 and 44 each with an annular series of slotports 45 and 46. Conical deflectors 50 may be mounted adjacent ports 45and 46, as shown, to cause local mixing of the issuing streams of air.Between the flanges of the bodies 43 and 44 are assembled a spacer ring47 with branch line 48 and the peripheral flanges 49 and 51 of tworolling seal members 52, 53.

The branch line 48 leads from any appropriate pressureregulating device,and could be branch line of pneumatic thermostat.

The rolling sleeve members 52 and 53 are cup-like members of rubber orsimilar resilient impervious material, preferably devoid of fabric orother reinforcements. The rolling folds of these members are oppositelyarranged as shown.

Associated with members 52, 53 are cylindrical sustaining members 54, 55of different diameters, assembled end to end and clamped upon centralportions of members 52, 53 by a stud 56 and nut 57. The members 43 and44 are in effect the cylinder of an expansible chamber motor, and themembers 54 and 55 the piston of that motor. Pressure developed in motorspace 58 by the admission and exhaust of pressure fluid through branchline 48 will urge the members 54, 55 to the left. To oppose this actiona coiled tension spring 59 is used. It is connected at one end to member55 and at the other end to the cross-pin 61.

The relative diameters of parts 44 and 55 and of 43 and 54 and thethicknesses of members 52 and 53 are so coordinated that the rollingfolds center the parts 56 and 54, afford rolling seals between therelatively moving parts and act progressively to obstruct and expose theports 46 and 45. The parts 52 and 53 are so dimensioned and the ports45, 46 so located that closing of ports 45 proceeds as opening of ports46 takes place and vice versa. The shape and dimension of the ports 45,46 can be chosen to afford desired flow characteristics, as alreadyexplained.

In some cases it is desirable to have the moving parts and the sealsexternal to the duct. Fig. 2 shows an arrangement of this type. I

The two valve bodies 91 and 92 have ports 93 and 94. Their ends areclosed and clamp between them the two rolling seals 95 and 96. The ductsare of different diameters and are encircled by sleeves 97, 98 (also ofunequal diameters) which shift together and outwardly confine therolling seals 95, 96. The sleeves 97, 98 have flanged ends connected tospacer ring 99 and serving to clamp to it the marginal flanges of theseals 95, 96. The sleeves 97, 98 constitute the cylinder of anexpansible chamber motor, and the valve bodies 91, 92 constitute thepiston of that motor.

The flexible branch line 101 leads to the motor chamber 102. Two biasingsprings 103 are used and react between assembly 97, 98, 99, and a fixedyoke 104. The valve action is the same as that described for Fig. 2, oneset of ports starting to open as the other starts to close.

The concept can be variously embodied and has the advantage ofcompactness, silence of action, large port area, absence of mechanisminterposed between the motor and the valve or valves and above all lowinternal friction, so that its response is subject to minimumpracticable lag.

I claim:

1. A combined mixing valve and pressure-motor comprising in combination,two axially alined connected tubular members, each having an annularseries of ports; means obstructing communication between said tubularmembers; a generally cylindrical member coaxial with said members andmovable axially relatively thereto, said cylindrical member being sodifferentiated in diameter from the two tubular members as to aifordsubstantial annular clearance between each tubular member and thecylindrical member; two rolling seals each bridging a corresponding oneof said annular clearances, and each comprising tubing of rubber-likematerial turned through itself to afford a rolling fold which yieldinglyreacts ra- Patented Oct. 11, 1955.

dially on the cylindrical member and on the corresponding tubularmember, to which respectively the tubing is sealed at opposite sides ofthe fold, said rolling seals defining between them a diiferential motorspace whose volume varies as a consequence of said axial motion, theparts being so dimensioned and arranged that said axial motion causessaid rolling seals progressively to expose one and progressively tocover the other series of ports; means for admitting and exhaustingpressure fluid to and from said motor space; and yielding means forbiasing the parts in opposition to forces developed by pressure in saidmotor space.

2. The combination of two couples each comprising two coaxial members,namely a piston and an encircling cylinder so differentiated in diameteras to afford an intervening annular clearance, said members beingmovable relatively to one another in the direction of their common axis,one of the members of each couple having an annular series of ports, thepiston members of the two couples being connected to move in unisonrelatively to said cylinder members and being characterized by unequaldiameters and the cylinder members of the two couples being connected tomove in unison relatively to said piston members and being characterizedby similarly unequal diameters; two rolling seals one bridging each ofsaid annular clearances, both seals being located intermediate saidseries of ports and each seal comprising a tube folded through itselfand adapted to roll into and out of obstructive relation with acorresponding one of said two series of ports; means for admitting andexhausting motive fiuid to the space within said cylinders between thetwo seals; and yielding means reacting on said couples to oppose theaction of said motive fluid.

References Cited in the file of this patent UNITED STATES PATENTS1,851,062 Protzer Mar. 29, 1932 2,209,844 Otto July 30, 1940 2,343,584Scheele Mar. 4, 1944

